In the related art, continuous heating furnaces configured to heat a radiator using combustion heat obtained by combusting a fuel gas, and heat conveyed baking objects such as industrial materials, foods, or the like using radiant heat from a radiation surface of the radiator are common. Among the baking objects, some baking objects should not be exposed to a fuel gas or an exhaust gas. For this reason, in the continuous heating furnace, a design configured to prevent the fuel gas or exhaust gas from being mixed with the atmosphere around the baking object may be required.
Here, a continuous heating furnace in which a combustion chamber in which a fuel gas is combusted is isolated from a heating chamber into which a baking object is conveyed has been proposed (for example, see Patent Document 1). In the continuous heating furnace, radiation surfaces are disposed at upper and lower sides in a vertical direction of the heating chamber configured to heat the baking object, and the baking object is heated using radiant heat from the radiation surfaces. A high temperature exhaust gas generated by combusting the fuel gas flows in back sides of the radiation surfaces.